This invention relates to a water jet propulsion unit and more particularly to an improved reverse thrust bucket actuating the mechanism for such a unit.
Water jet propulsion units are well known and widely utilized for water vehicles. These units conventionally employ an impeller housing in which an impeller is contained and which draws water through a water inlet and which discharges it through a discharge nozzle for propulsion of the watercraft. Conventionally, a steering nozzle is mounted for pivotal movement about a vertically extending axis on the discharge nozzle of the jet propulsion unit so as to steer the associated watercraft. In conjunction with these types of arrangements, frequently there is also pivotally supported on the steering nozzle a reverse thrust bucket which cooperates with the steering nozzle so as to redirect the water issuing from the jet propulsion unit discharge nozzle so as to achieve a reverse thrust.
Since the steering nozzle is pivotally supported and is operated remotely as is the reverse thrust bucket, there then arise certain difficulties in positioning all of the control mechanism. That is, the mechanism for actuating the reverse thrust bucket, which pivots about a horizontally disposed axis, must not interfere with the mechanism that affects the steering of the watercraft and must also be effective to permit the reverse thrust bucket to pivot along with the steering nozzle. For this reason, it has been the normal practice to employ a flexible wire actuator for achieving both the steering operation and the operation of the reverse thrust bucket. However, the physical relationships with prior art constructions have been such that the reverse thrust bucket actuating flexible cable must extend along the upper end of the jet propulsion unit. In order to achieve good operation, the flexible actuator must be positioned at a fairly high height above the jet propulsion unit and this gives rise to obvious spatial problems.
It is, therefore, a principal object of this invention to provide an improved arrangement for actuating the reverse thrust bucket of a jet propulsion unit for a watercraft.
It is a further object of this invention to provide an improved and compact actuating mechanism for the reverse thrust bucket of a watercraft jet propulsion unit.
As has been previously noted, the reverse thrust operation is achieved by pivoting the reverse thrust bucket into confronting relationship of the discharge opening of the steering nozzle. As a result, there are substantial forces that act upon the reverse thrust bucket and which, in normal instances, tend to force the reverse thrust bucket back out of its neutral position. Although locking mechanisms may be employed, this can complicate the structure and also make the operation of the reverse thrust bucket more difficult.
Also, it is desirable to ensure that the reverse thrust bucket is held in its normal position when reverse operation is not required. This can result in the need for additional locking mechanisms.
It is, therefore, a further principal object of this invention to provide an improved reverse thrust bucket actuating mechanism that will self-lock the reverse thrust bucket at least one of its positions.
It is a further object of this invention to provide an actuating mechanism for the reverse thrust bucket of a water jet propulsion unit that will lock the reverse thrust bucket inherently in its operative positions.